Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like, conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent structure. The absorbent structure is typically located between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer. The absorbent structure can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the trade name HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body exudate, especially when the absorbent article is being worn by a newborn or other very young wearers. Insult amounts in such wearers tend to be very small. Other wearers might also produce very small insults.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators include various passive indicators such as indicator strips, printing, or other devices within each absorbent article, requiring a caregiver to pay for the wetness indicator in each absorbent article whether or not the caregiver intends to use the wetness indicator. Wetness indicators may also include alarm devices that are designed to assist parents or attendants in identifying a wet diaper condition early on. These devices produce either a visual or an audible signal. Many of these devices rely on electronics, including conductive elements within each absorbent article that may increase the expense of the absorbent article.
Problems, however, have been encountered in designing a signaling device that can be used as desired but that does not appreciably increase the cost of each absorbent article, while providing a meaningful signal to the caregiver. In addition, passive indicators located adjacent the outer cover of an absorbent article allow a caregiver to recognize when the absorbent article has been insulted, but such indicators typically require sufficient liquid to soak through the entire absorbent structure of the absorbent article to reach the indicator on the inside of the outer cover before an indication can be produced.